A rigid anodized aluminum arm extension with a 1-inch ball at each end for connecting strobes or video lights on an underwater arm system. The 5-inch length helps position lighting to reduce backscatter and create lighting angles for wide-angle work. It has a slotted middle section for attaching accessories and is compatible with the Sliding Ball Mount for mid-arm repositioning. A groove and o-ring design prevents slippage and allows finger-tightening underwater. The parts are hard-coat type III anodized for durability.